<PAGE>

                                                                   Exhibit 10.35

                           ENZON PHARMACEUTICALS, INC.
               NON-QUALIFIED STOCK OPTION CERTIFICATE & AGREEMENT

                                                      GRANT DATE: JUNE 10, 2005

                                                      CERTIFICATE NO.: 0003414

<TABLE>
<CAPTION>
         -------------------------------------------------------------------------------------------------
                            SUMMARY GRANT INFORMATION
         -------------------------------------------------------------------------------------------------
<S>                                                    <C>
         EMPLOYEE:                                     Craig A. Tooman
         --------------------------------------------- ---------------------------------------------------
         NUMBER OF SHARES:                             50,000
         --------------------------------------------- ---------------------------------------------------
         EXERCISE PRICE:                               $5.73
         --------------------------------------------- ---------------------------------------------------
                                                       1987 Non-Qualified Stock Option Plan, as amended
         PLAN:                                         (the "Plan")
         --------------------------------------------- ---------------------------------------------------
         OPTION                                        June 10, 2015 (subject to earlier termination, as
         TERMINATION DATE:                             set forth herein)
         --------------------------------------------- ---------------------------------------------------
</TABLE>

<TABLE>
<CAPTION>
         -------------------------------------------------------------------------------------------------
                               VESTING INFORMATION
         -------------------------------------------------------------------------------------------------
<S>                                                    <C>
                                                               Number of Shares to which the Option
                             Date                                      Becomes Exercisable
         --------------------------------------------- ---------------------------------------------------
                        June 10, 2006                                        12,500
         --------------------------------------------- ---------------------------------------------------
                        June 10, 2007                                        12,500
         --------------------------------------------- ---------------------------------------------------
                        June 10, 2008                                        12,500
         --------------------------------------------- ---------------------------------------------------
                        June 10, 2009                                        12,500
         --------------------------------------------- ---------------------------------------------------
</TABLE>

         In accordance with the terms and conditions of the Plan, the Employment
Agreement between Employee and the Company dated January 5, 2005, as amended of
even date herewith ("Employment Agreement"), and the mutual promises and
undertakings contained in the attached pages, intending to be legally bound, the
parties hereto agree to the provisions set forth in the Option Terms attached
hereto.

         IN WITNESS WHEREOF, the parties hereto have executed this Agreement as
of the date set forth above.


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<PAGE>

ENZON PHARMACEUTICALS, INC.                          EMPLOYEE


By: /s/ Paul Davit                                   /s/ Craig A. Tooman
    --------------------------------                ----------------------------
      Paul Davit                                     Signature
      Executive Vice President, Human Resources     ___________________________
                                                     Date June 10, 2005

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<PAGE>

                      1987 Non-Qualified Stock Option Plan
                                  Option Terms

         1. Grant of Option. The Company hereby grants Employee the right and
option (the "Option") to purchase all or any part of an aggregate of the number
of shares of the Company's common stock, par value $0.01 per share (the "Common
Stock") set forth above, at the price per share set forth above (the "Exercise
Price") on the terms and conditions set forth in this Agreement, in the Plan and
in the Employment Agreement. It is understood and agreed that the Exercise Price
is the per share Fair Market Value (as defined in the Plan) of such shares on
the date of this Agreement. The Option is not intended to be an Incentive Stock
Option within the meaning of Section 422 of the Internal Revenue Code of 1986,
as amended (the "Code"). The Option is issued pursuant to the Plan and is
subject to its terms. A copy of the Plan has been furnished to Employee.
Employee hereby confirms he/she has received and thoroughly read the Plan. The
Company invites and encourages Employee to contact any member of the Company's
Human Resources Department with any questions he/she may have regarding the Plan
or this Agreement.

         2. Expiration. The Option shall terminate at the close of business on
the termination date set forth above or earlier as is prescribed in the Plan or
herein. Employee shall not have any of the rights of a stockholder with respect
to the shares subject to the Option until such shares shall be issued to
Employee upon the proper exercise of the Option.

         3. Vesting of Option Rights. Except as otherwise provided in Section 4
of this Agreement, the Option shall become exercisable in portions in accordance
with the schedule set forth above, provided the Employee is employed by the
Company on the vesting date in question.

         4. Vesting and Exercise of Option after Termination of Employment. The
acceleration of the vesting and exercisability of this Option upon a termination
of Employee's employment or the occurrence of a Change of Control shall be as
set forth in the Employment Agreement. The duration of the exercisability of
this Option, to the extent vested and exercisable, after termination of
Employee's employment with the Company shall be (a) as set forth in the
Employment Agreement in the case of a termination of employment pursuant to
Section 10(d) (Disability) or 10(e) (Without Cause, For Good Reason) of the
Employment Agreement, (b) until June 10, 2015 in the case of Employee's death
while employed by the Company or his death within three months after the date of
his retirement from the Company and (c) in all other cases shall be exercisable
for one hundred ninety days following termination of employment. The foregoing
to the contrary notwithstanding, the Option, to the extent then vested, shall in
no case be exercisable (i) prior to December 10, 2005 or after June 10, 2015.

         5. Transfer and Assignment. This Option may not be transferred except
in accordance with the terms of the Plan. The terms of this Option shall be
binding upon the executors, administrators, heirs, successors, and assigns of
the Employee.

         6. Method of Exercise of Option. The Option may be exercised in whole
or in part from time to time by Employee or other proper party in accordance
with the terms of the Plan by serving written notice of exercise on the Company
at its principal office within the period during which the Option is exercisable
as provided in this Agreement. The notice shall state the number of shares as to
which the Option is being exercised and shall be accompanied by payment in full
of the Exercise Price for all shares designated in the notice. Payment of the
Exercise Price shall be made in cash (including bank check, personal check or
money order payable to the Company), or otherwise in accordance with the Plan.
This Option shall be exercised only for 100 shares of Common Stock or a multiple
thereof or for the full number of shares for which the Option is then
exercisable.

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<PAGE>

         7. Miscellaneous.

                  (a) In the event that any provision of this Agreement
         conflicts with or is inconsistent in any respect with the terms of the
         Plan, the terms of the Plan shall control. To the extent there is any
         conflict among the provisions of this Agreement and those of the
         Employment Agreement, the Employment Agreement shall control.

                  (b) Neither the Plan nor this Agreement shall (i) be deemed to
         give any individual a right to remain an employee of the Company, (ii)
         restrict the right of the Company to discharge any employee, with or
         without cause, or (iii) be deemed to be a written contract of
         employment.

                  (c) The exercise of all or any parts of the Option shall only
         be effective at such time that the sale of shares of Common Stock
         pursuant to such exercise will not violate any state or federal
         securities or other laws. This Option may not be exercised if the
         issuance of shares of Common Stock of the Company upon such exercise
         would constitute a violation of any applicable Federal or state
         securities or other law or valid regulation. The Employee, as a
         condition to his or her exercise of this Option, shall represent to the
         Company that the shares of Common Stock of the Company that he or she
         acquires under this Option are being acquired by him or her for
         investment and not with a view to distribution or resale, unless
         counsel for the Company is then of the opinion that such a
         representation is not required under the Securities Act of 1933, as
         amended (the "Act") or any other applicable law, regulation, or rule of
         any governmental agency and shall, if the shares of Common Stock
         underlying this Option are not registered under the Act, acknowledge
         that the certificate evidencing such shares may be stamped with a
         restrictive legend and such shares will be "restricted securities" as
         defined in Rule 144 promulgated under the Act.

                  (d) The Company shall at all times during the term of the
         Option reserve and keep available such number of shares of the
         Company's Common Stock as will be sufficient to satisfy the
         requirements of this agreement.

                  (e) In order to provide the Company with the opportunity to
         claim the benefit of any income tax deduction which may be available to
         it upon the exercise of the Option and in order to comply with all
         applicable federal or state income tax laws or regulations, the Company
         may take such action as it deems appropriate to insure that, if
         necessary, all applicable federal or state payroll, withholding, income
         or other taxes are withheld or collected from Employee.

                  (f) The Company, in its sole and absolute discretion, may
         allow Employee to satisfy Employee's federal and state income tax
         withholding obligations upon exercise of the Option by (i) having the
         Company withhold a portion of the shares of Common Stock otherwise to
         be delivered upon exercise of the Option having a Fair Market Value
         equal to the amount of federal and state income tax required to be
         withheld upon such exercise, in accordance with such rules as the
         Company may from time to time establish, or (ii) delivering to the
         Company shares of its Common Stock other than the shares issuable upon
         exercise of the Option with a Fair Market Value equal to such taxes, in
         accordance with such rules.

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